Lubricating oil additives



Patented Sept. 7, 1954 2,688,596 LUBRICATING oIL ADDITIVE-S Esther M. Defifley,

Elizabeth, N.

J., .assignor to Standard Oil Development Company, a corporation of Delaware N Drawing. Application May 11, 1950, Serial No. 161,483

4 Claims. (Cl. 252*52) This invention relates to lubricating oil additives and to their method of manufacture. More particularly, this invention relates to a method for the preparation of lubricating oil additives having increased stability characteristics.

It has been known in the art of lubricating oil manufacture that valuable improvements in de sirable characteristics of lubricating oils can be obtained by incorporating with a suitable base stock minor percentages of polymers of vinyl ethers and particularly polyvinyl ethers of saturated alcohols. The preparation of these compounds is well described in the patent literature. For instance, U. S. Patent No. 2,061,934, issued to Conradi et al. on November 24, 1936, describes the low temperature polymerization of vinyl isobutyl ether.

These polyvinyl ethers have the desirable characteristic of imparting to the base stocks with which they are blended resistance to viscosity change with changing temperature, a characteristic known to the art as viscosity index improvement.

It has been found subsequently, however, that these polyvinyl ethers, and particularl polyvinyl isobutyl ether, are quite susceptible to shear and thermal breakdown, that is to say, when base stocks containing these polyvinyl ethers are subjected to conditions of high shear and high temperature, there tends to be a decrease in their resistance to viscosity change with temperature change and a consequent loss in viscosity at higher temperatures.

It has now been found that .these polyvinyl ether type viscosity index improvers may be proved when subjected to vention. The preferred embodiment contemplates the heat treating of polyvinyl ethers of saturated alcohols having from 4 to 8 carbon atoms. Particularly operable are the polyvinyl isobutyl ethers having molecular weights ranging from 7,000 to 40,000 Staudinger and of these, those polyvinyl ethers having molecular weights ranging from 20,000 to 35,000 are especially improved.

The polyvinyl ethers are easily prepared by known methods. For example, the monomers can be prepared by reacting acetylene with an ppropriate alcohol in the presence of a sodium alcoholate catalyst, and the monomers can be polymerized in the presence of a Friedel-Crafts catalyst, such as BF's, A1013, ZnClz, etc. at a suitable temperature in the range from -40 C. to C.

The following experimental data indicates more specifically the operability of this improved proaess.

EXAMPLE I A polyvinyl isobutyl ether, having a molecular weight of about 33,500, prepared according to known procedures, was blended in varying corrcentrations in a phenol extracted Mid-Continent distillate having a viscosity at 210 F. of 46 S. U. S. and a viscosity index of 112. Inspection tests on these blends point out the viscosity index improving potency of this polymer.

Table I Concentration of Active Via, 25 F., Vis., 100 'F., Vis., 210 F., Viscosity Ingredient S. U. S. S. U. S. S. U. S. Index EXAMPLE II stabilized against shear and thermal breakdown by a heating step.

In this stabilizing process the polyvinyl ether, either in the form of the copolymer itself or in an oil concentrate of the copolymer containing from 10% to 99% by Weight of the copolymer, is heated to a temperature of from 50 C. to 100 0., preferably C. to C., for a period of time within a range of from 20 to 60 hours, preferably 40 to 50 hours.

Any of the polymerized vinyl ethers having vis- A 2.0 weight butyl ether of base stock a blend of percent blend of the polyvinyl iso- Example I was made using as a Mid-Continent and Coastal distillates, the base stock having a viscosity at 210 F. of 57.2 S. U. S. and a viscosity index of 92. This blend of polymer and oil base was divided into two portions. One portion was submitted to the McIntyre pump test for one hour wherein the polymer oil blend is circulated through the McIntyre gear pump at 200 F. and

2,688,596 3 4 1000 P for One A o pa i i from 50 C. to 100 C. for from 20 to 60 hours the viscosity data on the two portions were then said polymer having a molecular weight within made, the data being reported in Table II bethe range of from 20,000 to 35,000.

- 2. A process according to claim 1 wherein said low.

Table II Breakdown, Vis., 210 F., Viscosity A Viscosity Percent Loss s. U. s. Index Index in Via, 210 F., s. U. s. Original Sample 77. 9 126. 0 1 Hour Sample 73.1 l20.1 5.9 23

EXAMPLE III polymer is heated to a temperature from 60 C. to 70 C. for from to 40 hours.

ified The same polyvmyl Isobutyl ether Idem m 3. A process for the stabilization of polyvinyl Example I above was blended with a close out solvent extracted Mid-Continent stock to form a lsobutyl ether havmg. molecplar welght of about 20 weight percent blend. This oil concentrate of g f fi l sg g i sfi g g zgfi thepolyvinyl isobutyl ether was heated in an oven 20 ether to a tempei ature within a r ange froi n 9 802 1 maintained at 65 C. for a period of 48 hours. 500 C to 100 C for from 20 to 60 hours After the heat treatment was completed, a 2.0

weight percent blend of the concentrate in a blend 1 sfi for g g T i of Mid-Continent and Coastal distillates having a g 2 'g z' 522583 2 3 5 Eag g g sgg g z g fig g ggf j iii g 5 2 53 3 paring a mineral oil blend containing about 20% of said polymer and heating said mineral oil blend divided into two portions. One portion was submitted to the McIntyre pump test as described to a temperature within a range of from about in Example II above. At the expiration of this 110 C311)r from 20 to 60 hours d P 3- test the two portions were again compared and mer having a molecular weight within the range the comparative data reported in Table III below. of from 20,000 to 35,000.

Table III Breakdown,

Vis.,210 F., Viscosity AViscosity Percent Loss S. U. S. Index Index 21 Original Sample 76.9 122. 6 1 Hour Sample 74. 8 121. 6 1.0 10.6

A comparison of the data reported in Table II References Cited in the file of this Patent and Table III will show the outstanding improve- UNITED STATES PATENTS ment in stability obtained by the process of this invention. The percent loss in viscosity at 210 Numbel Name Date F. was reduced from 23% to 10.6%, the viscosity 2,020,703 Schumann et a1 12, 1935 index differential being reduced from 5.9 to 1.0. 2,020,714 W at 12, 1935 To summarize briefly, this invention relates to 1085525 a1 J1me 29, 1937 an improved lubricating oil additive and to lu- 2,239,501 et a1 P 1941 bricating oils containing such improved additive. 2484374 scmmknecht Sept 1949 Polyvinyl ether type additives are greatly im- 2,551,467 Schfldknecht May 1, 1951 proved in stability by being subjected to a heat FOREIGN PATENTS treatment Number Country Date,

What is claimed is: 1. A process for the stabilization of polymers of 455340 Canada 1949 vinyl ethers containing from 3 to 12 saturated OTHER F ENCES carbon atoms which comprises heating a mate- Schmidt et a1., Principles of High-Polymer rial consisting essentially of an oil solution of Theory nd Practice, McGraw-I-Iill, 1948, pages said polymer to a temperature within a range 237 and 239, 

1. A PROCESS FOR THE STABILIZATION OF POLYMERS OF VINYL ETHERS CONTAINING FROM 3 TO 12 SATURATED CARBON ATOMS WHICH COMPRISES HEATING A MATERIAL CONSISTING ESSENTIALLY OF AN OIL SOLUTION OF SIAD POLYMER TO A TEMPERATURE WITHIN A RANGE FROM 50* C. TO 100* C. FOR FROM 20 TO 60 HOURS SAID POLYMER HAVING A MOLECULAR WEIGHT WITHIN THE RANGE OF FROM 20,000 TO 35,00. 